This proposal describes a browser-based tool for improving English writing and composition skills. The tool, Composition Corrector, uses an innovative technology to correct written English grammar and provide grammatical examples for each corrected grammatical pattern. The tool is aimed at a critical and underserved population - profoundly deaf students who communicate fluently in American Sign Language (ASL). English grammar and composition skills of deaf students are consistently reported as 4 -7 grades behind those of their hearing counterparts. This handicap is a significant impediment to higher education and access to many professions. Writing correct and clearly focused English will contribute to deaf students' independence, quality of life, and professional advancement. The Composition Corrector is a computer-based "writing tutor" for students to use in self-study programs, classroom practice, and in sessions with language instructors. In Phase I its operation is based on correspondences and differences between ASL and written standard American English. In later phases its commercial scope will be expanded to provide a convenient tool for ESL and other languages for use in the home, at school, and in corporate settings for the correction of business documents. Phase I focuses on concept feasibility: collecting a body of English essays written by students whose first language is ASL, documenting consistent non-standard but typical patterns, developing a prototype system that identifies and corrects several of the most common errors, and testing the prototype's ability to provide correct and usefully presented standard English instruction for deaf students. Phase II will produce a working prototype of the Composition Corrector with an expanded set of corrected patterns and an effective user interface. Phase II will also investigate the application of the tool for ESL applications in home, school, and corporate settings.